Biology subjects

Ku, E.

Publications and source records attributed to Ku, E..

3 recordsLinked to original sources

bioRxiv2026

CA19-9 induces microenvironment remodeling in pancreatic ductal adenocarcinoma

Durable therapeutic efficacy remains a major barrier to improving outcomes for patients with pancreatic ductal adenocarcinoma (PDAC). An immunosuppressive tumor microenvironment (TME) is a hallmark of PDAC and has been demonstrated to be a dominant driver of therapeutic resistance. The aberrant glycan CA19-9 is prevalent in PDAC and drives tumor progression, but the paracrine mechanisms by which it contributes to TME remodeling are unknown. To address this, we mapped TME changes and performed functional analyses using a genetically engineered mouse model (GEMM) harboring KrasG12D mutation and inducible CA19-9 expression. Elevation of CA19-9 led to expansion of antigen-presenting cancer associated fibroblasts (apCAFs) and regulatory T cells (Tregs), which can drive immunosuppression. Antibody blockade of CA19 -9 resulted in significant restoration of normal histology and decreased apCAF and Treg populations. We dissected the paracrine signaling mechanisms that drive this TME remodeling in vitro using mouse and human organoid mono- and co-culture models as well as in vivo using GEMMs and syngeneic orthotopic transplantation models. CA19-9 induced IL1a and TGFb expression, reprogramming pancreatic mesothelial cells into apCAFs in vitro, which in turn directly ligated naive Cd4+ T cells resulting in Treg differentiation in co-cultures. Antibody blockade of IL1a and TGFb in mice led to reduced apCAF and Treg differentiation. We previously reported that CA19-9 modification of the secreted Fbln3 protein increased Egfr engagement and now find that the induction of IL1a and TGFb expression by CA19-9 is dependent on Fbln3 hyperactivation of EGFR signaling. Genetic depletion of Fbln3 led to reduced tumor progression and increased Cd8+ T cell infiltration in mice. Together these findings identify a previously unknown signaling axis driving immunosuppressive phenotypes in PDAC, uncovering multiple potential nodes to relieve the immunosuppressive pressures within the PDAC TME.

cancer biology↗

bioRxiv2024

BPMs regulate Arabidopsis seedling development by promoting auxin-independent degradation of the Aux/IAA protein IAA10

After germination, seedlings undergo etiolated development (skotomorphogenesis), enabling them to grow towards the soil surface. In Arabidopsis, etiolated seedlings exhibit rapid hypocotyl elongation, apical hook formation and closed cotyledons to protect the meristem. In this study, we found that high-order mutants in the BPM gene family displayed defects in seedling development, characterized by a shorter hypocotyl, early apical hook opening, and opened cotyledons in the dark. BPM1, BPM2, BPM4, and BPM5 exhibit distinct expression patterns and subcellular localization in etiolated seedlings. In a hypocotyl segment assay the bpm mutants showed defects in auxin response indicating impaired auxin signaling in the hypocotyl. Expression of the auxin reporter DR5:GFP was also altered in the bpm1,4,5 mutant in various tissues compared to the wild type. Furthermore, we showed that BPM1 and IAA10 interact in yeast two-hybrid, BiFC, and Co-IP assays. Experiments in protoplasts indicated that BPM1 promotes ubiquitylation and degradation of IAA10, and the level of IAA10 protein is greater in the bpm1,4,5 mutant. In addition, IAA10 over-expression resulted in phenotypes similar to the bpm mutants. These results indicate that the BPMs target the Aux/IAA proteins for ubiquitylation and degradation. Overall, our findings shed light on the key roles of the BPMs in auxin signaling during seedling development.

plant biology↗

bioRxiv2021

Protease activities of vaginal Porphyromonas species disrupt coagulation and extracellular matrix in the cervicovaginal niche

Porphyromonas asaccahrolytica and Porphyromonas uenonis are frequently isolated from the human vagina and are linked to bacterial vaginosis and preterm labour. However, little is known about the pathogenesis mechanisms of these bacteria. The related oral opportunistic pathogen, Porphyromonas gingivalis, is comparatively well-studied and known to secrete numerous extracellular matrix-targeting proteases. Among these are the gingipain family of cysteine proteases that drive periodontal disease progression and hematogenic transmission to the placenta. Given their phylogenetic relatedness, we hypothesized that vaginal Porphyromonas species possess gingipain-like protease activity targeting host extracellular matrix in the female reproductive tract. In this study, we demonstrate that vaginal Porphyromonas species degrade type I collagen (cervix), type IV collagen (chorioamnion/placenta), and fibrinogen, but not through the activity of gingipain orthologs. Bioinformatic queries identified 5 candidate collagenases in each species, including serine, cysteine and metalloproteases, with signal peptides directing them to the extracellular environment. Inhibition assays revealed both species secrete metalloproteases that degrade collagen and casein, while P. asaccharolytica also secretes a metalloprotease that degrades fibrinogen. Phylogenetic analysis of the predicted collagen-degrading metalloprotease revealed an orthologous relationship with the P. gingivalis endopeptidase PepO. Cloning and expression of P. asaccharolytica PepO confirmed this proteins collagenase and caseinase activities, which have not previously been attributed to PepO homologs in other bacteria. Altogether, this description of the first known virulence factor in Porphyromonas species colonizing the human vagina sheds light on their potential to alter the structural integrity and homeostasis of reproductive tissues. ImportancePorphyromonas species are common inhabitants of the vaginal microbiome, but their presence has been liked to adverse health outcomes for women, including bacterial vaginosis and preterm birth. We determined that P. asaccharolytica and P. uenonis secrete broad-acting proteases capable of freely diffusing within the cervicovaginal niche and degrading important components of host tissues, namely the extracellular matrix. We show that secreted Porphyromonas proteases degrade collagens that are enriched within the cervix (type I) and chorioamniotic membranes (type IV). Furthermore, these Porphyromonas proteases can also degrade fibrinogen and inhibit clot formation. These activities can be partially attributed to a metalloprotease that exhibits broad-acting protease activity and is distantly related to the P. gingivalis endopeptidase PepO. This initial characterization of virulence activities in vaginal Porphyromonas species highlights their potential to harm human pregnancy through clotting disruption, fetal membrane weakening, and premature cervical remodeling.

microbiology↗